This invention relates to vascular catheters (such as angioplasty catheters) specially adapted for rapid exchange of both the guidewire and the catheter during use. It also relates to the method of using those catheters.
Percutaneous transluminal coronary angioplasty (PTCA) has emerged as the major viable present alternative to bypass surgery for revascularization of stenotic and occluded coronary arteries. Although transluminal angioplasty has application in peripheral artery disease, it is most widely used in the treatment of coronary artery disease. Unlike bypass surgery, percutaneous angioplasty does not require general anesthesia, cutting of the chest wall, extracorporeal perfusion, or transfusion of blood. Percutaneous coronary angioplasty is not only less invasive and less traumatic to the patient, it is also less expensive because the angioplasty patient will have a shorter hospital stay and shorter post-procedure recovery time.
Percutaneous transluminal angioplasty is performed by making a skin puncture with a specially-designed needle in one of the groins, and then introducing a guiding catheter (typically 8 or 9 French size) into the aorta and coronary artery orifice. A smaller caliber catheter which has a built-in inflatable and deflatable balloon of predetermined size and diameter is passed through the guiding catheter which is positioned in the opening of a target artery. This balloon catheter (with the balloon totally deflated by negative pressure) is advanced inside the target artery toward the point of obstruction that needs to be dilated. The guidewire plays an essential role in leading the balloon catheter to the target coronary artery in safety and non-traumatic fashion. With the balloon portion of the catheter properly positioned inside the obstructed segment of the artery, under X-ray fluoroscopic observation, the balloon is inflated by injecting contrast media mixed with saline at a pressure sufficient to overcome the resistance of the arteriosclerotic plaque of the obstructed segment.
By inflating the balloon in the stenosis multiple times over a period of between 10-30 seconds and one or two minutes (allowing blood flow between inflations), the desired dilation of the obstructed segment of the artery can be achieved. When the desired results have been obtained by balloon inflations, the guiding catheter, the balloon catheter (with the balloon completely deflated with negative pressure) and the guidewire are withdrawn from the artery and the patient, and the procedure is successfully terminated.
The size and diameter of the balloon to be used in a transluminal angioplasty should be approximately matched to the size and native diameter of the obstructed segment of the artery to be dilated. If the balloon size and diameter is smaller than the native artery, the results of balloon angioplasty are suboptimal, requiring a second dilation with a larger-sized balloon, and if balloon size is too large for the native artery, complications may occur due to arterial wall damage.
During the angioplasty procedure, a guidewire is first advanced into the desired location, after which the angioplasty catheter is advanced over the guidewire. It is sometimes necessary to replace (or exchange) either the guidewire or the balloon catheter during the procedure.
If the balloon is undersized, for example, the catheter must be withdrawn and replaced with a larger balloon catheter in order to permit adequate dilatation of the lesion. With conventional over-the-wire catheters, in which the guidewire lumen extends the entire length of the catheter shaft, a guidewire extension (e.g., 145 cm long) must first be attached to the regular guidewire (e.g., 175 cm long) being used outside the patient before the catheter is withdrawn. This permits the distal end of guidewire to be held in position while the catheter is removed and a new catheter is exchanged. Usually, two to three operators are needed to effect such a catheter exchange.
The catheter disclosed in U.S. Pat. No. 4,762,129 avoids the necessity for extending the guidewire or exchange guidewire (e.g., 300 cm in length) by having a short guidewire lumen that extends substantially only through the distal end of the catheter. This type of catheter is referred to herein as a rapid-exchange catheter. Thus, the guidewire is outside the catheter shaft for much of the catheter length, and is inside the catheter at only the distal end. The catheter can be exchanged without extending the 175 cm regular guidewire, and the exchange can be effected by one or two operators. However, this catheter has a serious drawback of not being able to permit ready exchange of guidewires. In clinical practice, the need for guidewire exchange is more common.
Conventional over-the-wire angioplasty catheters, with a guidewire lumen extending their entire length, permit simple guidewire exchange. During angioplasty procedures, the guidewire tip may become damaged, may be needed of a different type of guidewire or may need to be reshaped to complement the patient""s vasculature. The guidewire exchange procedure is readily accomplished with such a conventional over-the-wire catheter. However, with the rapid-exchange type catheter of U.S. Pat. No. 4,762,129, guidewire exchange requires complete removal and reinsertion of both the guidewire and the angioplasty catheter; thus, defeating the original goal of expedient advantage of the rapid-exchange catheter.
Another disadvantage of the rapid-exchange catheter is back bleeding. While the guidewire is being manipulated to select the target vessel or to cross the culprit lesion, the Tuehy-Borst adapter must be loosened. This, in turn, permits backbleeding to occur.
Accordingly, there is a need for an angioplasty catheter that permits rapid-exchange of both the catheter and the guidewire. There is also a need for a catheter that will permit the user to select the mode of usage between the rapid-exchange and the over-the-wire systems.
In accordance with one aspect of the present invention, there is provided an angioplasty catheter comprising a catheter shaft having a proximal portion and a distal end, an angioplasty balloon attached to the shaft at the distal end, a balloon inflation lumen extending through the shaft and communicating with the interior of the balloon, a guidewire lumen extending through the shaft and through the balloon for receiving a steerable guidewire, the guidewire lumen having an outside wall, wherein the guidewire lumen has a proximal opening located at a point normally outside of the patient during use of the catheter for insertion of a guidewire into the lumen, and a side port adapted to permit passage of a guidewire into the lumen through the outside wall of the guidewire lumen, the side port located distally of the proximal opening and at a point normally inside of the patient during use, and guidewire removing means in the outside wall of the guidewire lumen extending from the proximal opening to the side port for permitting a guidewire in the guidewire lumen to be moved laterally from the guidewire lumen though the outside wall of the guidewire lumen. In one embodiment, the side port is located adjacent to and proximally of the balloon, preferably within about 35 cm of the balloon. One embodiment of the guidewire removing means is a slit through the outside wall of the catheter shaft. This slit may be continuous from the proximal opening to the side port, or may be discontinuous, forming a perforated line from the proximal opening to the side port. In another embodiment, the guidewire removing means is a weakened area of the wall of the guidewire lumen adapted to be severed for removal of the guidewire therethrough. One variation of the invention provides a second side port communicating with the interior of the guidewire lumen. Another provides a perfusion opening communicating with the interior of the guidewire lumen, the perfusion opening located between the side port and the balloon. Still another embodiment includes a xe2x80x9cYxe2x80x9d connector at the proximal opening having an axial portion through which the balloon inflation lumen extends and a side portion through which the guidewire may be inserted into the guidewire lumen, wherein at least a portion of the connector can be removed from the catheter shaft to permit a guidewire extending through the connector and into the guidewire lumen to be removed through the guidewire removing means. The connector is advantageously adapted to be separated longitudinally and at least a portion thereof removed from the catheter shaft. In one variation, the connector comprises two longitudinally separable portions having first and second longitudinal sides on different sides of the catheter shaft, the portions being hingedly joined at the first longitudinal side and separably joined at the second longitudinal side.
Another embodiment of the present invention comprises an intravascular catheter comprising a catheter shaft having a proximal end and a distal end, wherein a portion of the catheter including the distal end is normally inside a patient during use and the proximal end is normally outside the patient or outside the guiding catheter, a guidewire lumen extending through the shaft for receiving a steerable guidewire, wherein the guidewire lumen has an outside wall, and a proximal opening at the proximal end of the shaft for insertion of a guidewire into the lumen, and means formed in the outside wall of the guidewire lumen extending distally from the proximal opening to a point normally inside the patient during use of the catheter for permitting a guidewire in the guidewire lumen to be moved laterally from the guidewire lumen though the outside wall of the guidewire lumen. The guidewire removing means may be a slit, fully formed or inchoate. The catheter preferably includes a side port through the outside wall of the guidewire lumen for passage of a guidewire into the lumen through the side of the catheter shaft, the side port located distally of the proximal opening and normally inside of a patient during use of the catheter. In one embodiment of the catheter, the guidewire removing means is a slit and the slit is continuous from the proximal opening to the side port. In another, the guidewire removing means is a slit and the slit is discontinuous, forming a perforated line from the proximal opening to the side port. In still another embodiment, the guidewire removing means is a weakened area of the wall of the guidewire lumen adapted to be severed for removal of the guidewire therethrough. According to one modification, the catheter may further comprise a second side port communicating with the interior of the guidewire lumen.
The present invention also includes a catheter for use in an animal body with a guidewire, comprising a catheter shaft having a proximal end and a distal end with at least two lumens extending therethrough, and a xe2x80x9cYxe2x80x9d connector surrounding at least a portion of the proximal end of the catheter shaft and having at least two arms, one arm providing an access channel into one of the lumens and another arm providing an access channel into another of the lumens, wherein the xe2x80x9cYxe2x80x9d connector has at least two segments joined together in a separable manner along a longitudinal line so that upon separation of the segments, the xe2x80x9cYxe2x80x9d connector no longer surrounds the portion of the proximal end of the catheter shaft. In one embodiment, upon separation of the segments, one of the segments is completely removable from the catheter shaft. In another embodiment, upon separation of the segments, the connector is completely removable from the catheter shaft in such a manner that an elongate object extending through one arm of the connector into a lumen of the catheter shaft can remain in the lumen during such removal of the connector.
The invention further includes a method of removing a catheter during a procedure involving vascular catheterization, comprising the steps of providing a catheter of the type described above having a guidewire passing through the guidewire lumen from the proximal opening to the distal opening thereof and positioning the catheter in a patient with the proximal end of the guidewire extending out of the proximal opening, holding the proximal end of the guidewire to maintain the positioning of the guidewire in the patient while removing the catheter from the patient by moving the guidewire laterally out of the guidewire lumen through the guidewire removing means until the entire catheter is outside the patient and outside the guiding catheter and a portion of the guidewire is exposed at the distal end of the catheter, and then holding the exposed portion of the guidewire and removing the catheter off of the proximal end of the guidewire. The method may also include inserting another catheter, with the guidewire in the guidewire lumen at the distal portion of the catheter and either remaining in the guidewire lumen for the entire length of the catheter that is inside the patient during use, or extending out through the side of the catheter and running parallel to the catheter proximal of the distal portion of the catheter.